I can't figure what's earth-friendly about the steel. It takes a lot of carbon to make that steel, and putting paper filters in landfills sequesters carbon (part of my entire theme that we should increase demand for any disposable carbon-based product that requires little energy to manufacture, and see to it that it's properly deposited in one of a vast number of landfills ;-)
Not to broach a hot topic; I just don't think it's possible to know enough to be content, with warrant, that either alternative is in the long run somehow more or less responsible for making things better or worse.
For me, the alternative to being more certain than is warranted is not to not give a rip, it's just to be content with not knowing.